Introduction

In fact, it is difficult to envisage any other method which allows widely spaced surface exploration of airless planetary bodies that is not prohibitively expensive.

Whilst the technology to achieve this is challenging, space qualified probes already exist, and the rapid pace of technology advance is likely to lead to significant improvements in microtisation and associated industrial spin-off.

Kinetic Micro-Penetrators

Kinetic micro-penetrators are tiny probes which impact planetary bodies at high speed and bury themselves into the planetary surface.

We are aiming at probe masses of around 2 to 12Kg with an additional similar mass to decelerate and align the probe to survive impact at around 300m/s (equivalent to around mach 1 on Earth). Survival of these impact speeds has been demonstrated by ground tests of full up NASA DS2 and Japanese Lunar-A probes, and extensive military experience of impacts into materials mostly consisting of concrete or steel.

Because they are small this allows many probes to be deployed at wide spacings across the planetary surface. They also naturally provide redundancy so no mission is vulnerable to the loss of a single probe.

Key Scientific Investigations

Whilst their small size does not allow a full complement of the most capable scientific instruments, they are ideal to perform focused investigations across widely space surfaces of the body not currently feasible with soft landers and rovers.

For example :-

For the Jovian satellite Europa, seismometers could determine the presence of an under-ice ocean, and the possible existence of an habit for extraterrestrial life, and organic chemical detection of the associated chemistry.

For the Moon, a seismic network could provide information into the origin of the Earth-Moon system, and ground truth as to whether water and other volatiles exists in permanently shaded areas in polar craters.

For NEOs (Near Earth Objects) this could confirm whether they are rubble piles consisting of rather loose agglomerates of rock and dust, or hard rocky bodies as originally thought.

Cost

There are several reasons why the use of micro-penetrators should be relatively inexpensive :-

The UK has access to extensive military experience over many years of high impact technology.

The UK has access to extensive space technology experience in both spacecraft and scientific instrument development.

Initial development of a generic airless penetrator will reduce development costs to delta levels for adaption to new planetary bodies.

Major costs are likely to be :-

Development of technologies which already exist but are not accessable.

Delta development of technologies to meet requirements of different planetary bodies.

Improvements to existing technologies to further reduce mass or improve performance.

Additional cost benefits are also envisaged, since technology developed for airless micro-penetrators are likely to benefit other lander and orbital missions for which robustness and very low mass are always advantageous. Also, only small additional developments would be required to extend this capability to exploration to planetary bodies having atmospheres.

Technology Readiness Levels

Though, as yet there has been no successful deployment of a high speed penetrator, and the only deployment, DS2(Deep Space-2) failed along with its companion lander, there is actually no evidence that these are inherently less reliable than soft landers.

In fact, both DS2 and the Japanese Lunar-A penetrators were space qualified, and there is a long history of successful technology operation on Earth from the firing of military shells.